Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Statement of Stockholders' Equity [Abstract]
Stock option exercises (shares)	491,675	1,249,874
Common stock issued in acquisition of WNB Bancshares (shares)	2,000,000	0
Issuance of preferred stock (shares)	0	6,000,000
Purchase of treasury stock (shares)	0	2,236,748
Cash dividends declared on preferred stock, per share	$ 1.01	$ 0.78
Cash dividends declared on common stock, per share	$ 1.52	$ 1.48